The glycocalyx is a gel-like layer lining the luminal surface of the endothelium. The glycocalyx exerts an important
barrier role because it prevents exposure of plasma components to the endothelial surface. Disruption of the glycocalyx
by local inflammation or ischemia results in decreased glycocalyx thickness which is associated with a number of
vascular diseases. The cerebrovascular glycocalyx has sparsely been studied, but is of great interest because of its potential
role in cerebrovascular disease. In this review, we describe all existing techniques to visualize the glycocalyx and designate
techniques that may be suitable for studying the cerebrovascular glycocalyx.
A total of seven imaging techniques are discussed thoroughly, including transmission electron microscopy, intravital microscopy,
micro-particle image velocimetry, confocal laser scanning microscopy, two-photon laser scanning microscopy,
orthogonal polarization spectral imaging and sidestream dark field/oblique imaging. Measurement of serum concentrations
of glycocalyx-specific constituents is another method for glycocalyx analysis. Also, we have reviewed the methods
of glycocalyx analysis by using these imaging techniques.
So far, the cerebrovascular glycocalyx has only been studied in vitro. However, other cerebral microcirculatory properties
have been studied in vivo. This suggests that the cerebrovascular glycocalyx can be studied in vivo by using some of the
described techniques, when specific software is subjoined to the analysis.
In conclusion, we have summarized techniques available for glycocalyx assessment, and explained the significance and
technical possibilities regarding cerebrovascular glycocalyx visualization. Cerebrovascular glycocalyx assessment would
add valuable information to our understanding of the pathophysiology of cerebrovascular disease. Moreover, as a part of
the blood-brain barrier, more knowledge on the cerebrovascular glycocalyx may lead to better understanding of neurodegenerative
conditions that are caused by a compromised blood-brain barrier including Alzheimer's disease, vascular dementia,
multiple sclerosis and epilepsy.